Submarine optical communication cables are optical cables laid on the sea bed connecting land-based stations. The optical communication cables carry signals across the ocean allowing for cable communication over the sea between different continents. Each submarine optical cable may include multiple (up to eight) pairs of fibers, each fiber of the fiber pair transmitting a signal in an opposite direction. The submarine optical communication cable is generally divided into multiple sections. Each section is connected to the other section by a submarine repeater. As the signals are carried across the ocean, the signals may lose some of their power. Typically, each submarine repeater includes multiple Erbium Doped Fiber Amplifiers (EDFA) and an amplifier for the signal in each fiber. Each EDFA has a gain sufficient to compensate for the loss experienced by the signal during its propagation in the previous section of optical fiber cable. For example, a typical length of a fiber cable section between repeaters is about 60 kilometers. As such, a typical cable with a length of 10,000 kilometers has about 166 repeaters. The repeaters ensure that the land-based station, receiving the signal from another land-based station, receives and understands the signal. In other words, the repeaters increase the power of the signal to compensate for any loss during the signal propagation. The increased power translates to higher capacity because the clearer and more precise the optical signal is, the more complex signals may be sent from one land-based station to another.
Referring to FIG. 1, a typical communication system 100 includes first and second trunk terminals 110, 110a, 110b (also referred to as stations) coupled to a communication trunk 102. The communication trunk 102 may include one or more repeaters 104. The repeaters 104 are powered by a constant current, typically one Ampere by power feeding equipment (PFE) 112, e.g., power source located by the shore. Due to nonzero electrical resistivity of copper, even with large copper area conductor having a resistance as low as 1 Ohm/kilometer, power feeding voltage drops by 60 Volts at each section of cable, so that about half of power feeding voltage is lost due to heat dissipation in copper for the cable. In some examples, each PFE 112 can provide power feed voltage of up to 14 kilovolts. Further increase of power feeding voltage to higher than 14 kilovolts may result in a fault during cable operation. The power feeding equipment 112 powers the repeaters 104 by a power cable 114, such as a copper cable.
Submarine optical communication cables have been traditionally designed to be highly engineered to obtain long lasting lives (about 24 years), have very high-availability, and minimal risk tolerance, which resulted in extremely high initial cable costs. Thus, due to the high initial cable cost, some intercontinental routes via the ocean are not viable from a business consideration. Furthermore, if one cable portion is undergoing a malfunction, then the entire cable fails to transmit the communication between the first and second trunk terminals 110a, 110b. Therefore, it is desirable to redesign the communication cable architecture to provide reliable, cost effective intercontinental communications, even when a portion of the cable fails to transmit a communication.